A study of the impact of cytokine gene polymorphism in acute rejection of renal transplant recipients

Acute rejection is a common phenomenon in transplantation. Inflammatory and anti-inflammatory mediators affect the graft microenvironment. Th1 responses cause acute rejection while Th2 immune responses help the survival of the graft. In this study, we evaluated gene polymorphisms of IL-6 G-174C, TGF-β T+869C, IL-4 C-590T, and IFN-γ T+874A cytokines in renal transplant patients. ARMS-PCR method was used to characterize IL-6 G-174C (rs76144090), TGF-β T+869C (rs1800471), and IFN-γ T+874A (rs2430561) polymorphisms and PCR-RFLP, for characterization of IL-4 C-590T (rs2243250) in 100 renal transplant patients. Acute rejection episodes were diagnosed according to the standard criteria. Analysis of the results showed that IL-6-174 GG genotype (P = 0.018, OR = 3.023, 95% CI = 1.183–7.726) and IL-6-174G allele (P = 0.046, OR = 2.114, 95% CI = 1.005–4.447) were more frequent, but IL-6-174GC genotype was less frequent in acute rejection of kidney transplantation in comparison with control group (P = 0.024, OR = 0.302, 95% CI = 0.103–0.883). IFN-γ+874 T allele was associated with a higher risk of acute rejection (P = 0.019, OR = 2.088, 95% CI = 1.124–3.880) while IFN-γ+874 AA genotype was associated with a lower risk of rejection (P = 0.023, OR = 0.318, 95% CI = 0.115–0.875). Frequencies of TGF-β T+869C and IL-4 C-590T were not significantly different (P > 0.05). Consequently, our results show that IL-6 G-174C and IFN-γ T+874A gene polymorphisms have predictive values for acute rejection after renal transplantation in Iranian patients.